The invention pertains to conduit fittings of the compression type usuable with a conventional flared fitting.
The well-known flared fitting is commonly employed in conduit systems, particularly those using soft metal conduit, such as copper tubing, and a flaring tool is utilized to form an annular flange on the end of the conduit which is held in metal-to-metal engagement with a conical surface designed on an adapter by means of a threaded nut mating with threads formed on the adapter.
While flared fittings are commonly employed for many types of installations, the formation of the flange is troublesome and time consuming, and must be carefully accomplished if a fluid tight connection is to be achieved. Considerable skill is required by the operator in forming the flared flange when done with hand tools at on-site locations and flared flanges cannot readily be made in close quarters.
Also, as the flared flange overlaps the conical sealing surface defined on the cooperating adapter fitting, in installations where two coaxially aligned flared conduits are interconnected by a conventional coupling or Tee the spacing between the ends of the conduits is less than the actual axial length of the coupling or Tee and difficulty is encountered in installing the same and preventing cross threading of the nuts.
While conduit fittings have been proposed for use with conventional flared adapters which do not employ a flared surface on the conduit, as shown in U.S. Pat. No. 2,930,635, such prior art devices require the use of a contractable ferrule mounted upon the conduit which is not freely axially positionable thereon, and clearance problems such as those described above still exist when utilizing this type of flareless fitting for interconnecting a pair of aligned conduits.